Phosphorins, phosphabenzene, phosphinine

Phosphorus. Substituted phosphorus analogues of pyridine (phosphinines, A3-phosphabenzenes, also called phosphonins or phosphorins) were first prepared by Markl starting from pyrylium cations their chemical properties suggest that their aromaticity is lower than that of pyridine (e.g. phosphinine 186, Scheme 72).230-232 Molecular calculations for other six-membered jr-systems with planar tricoordinate phosphorus, such as phospininines 186 and 187, have evidenced their aromaticity (Scheme 72).156... 

We carried out ab initio EOM-CCSD calculations to evaluate one-, two-, and three-bond 13C-13C, 15N-13C, 31P-13C coupling constants in benzene (161), pyridine (164, X = H), pyridinium (188), phosphinine (also called phosphabenzene and A,3-phosphorin) (189), and phosphininium (190). The introduction of N or P heteroatoms into the aromatic ring not only changes the magnitudes of the corresponding... 

At least three names are available for the compound H3P=CH2. These are phosphine methylene, methylene phosphonium ylid and phosphonium methylide moreover, the compound can be classed as a phosphorane The compound PhjP Rj may be called triphenylphosphonium methylide, tri-phenylphosphonium methanide or triphenyl-methylenephosphorane. The pyridine analogue, C5H5P, has been known variously as phosphobenzene, phosphabenzene, phosphorin, and most recently, phosphinine. The term phosphane for (1) in Table 1.4 and its derivatives is the most recent and the most systematic, but it is difficult to see how the more widespread and firmly rooted term phosphine will ever be replaced. In addition, adoption of the term phosphane would put it in line with such little-used terms as carborane for CH4, nitrane for NH3 and oxane for HjO. 

Many carbophosphorus ring compounds are known and the monophosphorus varieties include P atoms which are 2-connected as in phosphinine (also known as phosphorin or phosphabenzene) (6.9b), pyramidal as in phosphinane (also known as phosphorinane) (6.9a), tetrahedral as in hydroxyphosphinane oxide (6.9c), or trigonal bipyramidal as in cyclic tetramethylene trifluoro-phosphorane (6.9d). 

The use of conventional valence bond formulae for unsaturated rings containing carbon and one phosphorus atom leads to the arrangements indicated in Table 6.22. Derivatives of most of these ring systems are known, but phosphinine (also named phosphorin or phosphabenzene) represents the only parent compound synthesised to date. It is the analogue of pyridine, C5H5N, and arsenin,... 

In phosphinine (also called phosphorin or phosphabenzene) there is at least a formal resemblance to the situation in pyridine and benzene, and a planar ring system is to be expected. Crystal structure... 

Phosphinine (phosphorin or phosphabenzene), C5H5P, is a colourless volatile liquid which is very reactive, air-sensitive and characteristically odorous. It was first prepared by Ashe in 1970 [39] using reaction (6.860). Arsenin can be prepared by a similar reaction using arsenic trichloride. 

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